Manufacturing i-123-labelled radiopharmaceuticals. Pitfalls and solutions

A variety of radioiodination methods is described in the radiochemistry literature, however, only a few can fulfil manufacturing requirements. In this article we provide an overview of the process of preparing a radiopharmaceutical to inform the general reader in their everyday use of these products. According to molecular structure of the precursor/ligand, the first decision to be made is whether a nucleophilic or electrophilic approach should be used. Both are suitable for obtaining a high specific activity, as well as for integration in production processes. Feasible reaction conditions and reliability in terms of labelling yield and recovery are further relevant parameters. Recent changes and strengthening of the pharmaceutical regulations mean that I-123 radiopharmaceuticals are often autoclaved. In order to maintain the radiochemical purity during this process, as well as during storage/transport, radical scavengers or antioxidants have to be added. Copyright (c) 2005 John Wiley & Sons, Ltd.